1. `Field of the invention
The present invention relates to air conditioner systems for automotive vehicles, and more particularly to air conditioner systems capable of controlling the amount and temperature of the blown-out air for a rear-seat part separately from the amount and temperature of the blown-out air for a front-seat part of the vehicle passenger compartment.
2. Related Art
As shown in Japanese Utility Model laid-open Publication No. 57-97013, it is conventional practice to dispose two separate air conditioner units on a front-seat part and a rear-seat part, respectively, of the vehicle passenger compartment. The disclosed system is disadvantageous in that the front air conditioner unit is substantially useless in conditioning the rear-seat side and the air conditioner system is wasteful as a whole.
In order to eliminate the foregoing drawback, there have been proposed air conditioner systems such as shown in Japanese Patent Publication No. 58-7486 and the Japanese Patent Laid-Open Publication No. 57-167819. The former Publication shows a front-seat air conditioner unit which comprises at least one partition wall disposed in a main duct downstream of an evaporator so as to define a plurality of chambers or passages in which heater cores are disposed with air mix doors provided in front of the respective heater cores. The latter publication discloses a system wherein a heater core disposed in a main duct is subdivided into two portions, two air flow passages are defined downstream of the two heater core portions by means of a partition wall, and air mix doors are provided in front of the respective heater core portions to control the temperature of air passing through the respective passages.
Both disclosed systems have main ducts subdivided into plural chambers or passages so that the ducts are complex in construction. Since the amount of air blown from outlets of the duct reduces as the number of passages increases, an insufficient amount of air is blown into the rear-seat part when a large amount of air is blown into the front-seat part. Thus a difficulty arises in that proper control of the amount of blown-out air is difficult to achieve.